The pair were due to see their loan deals expire after Saturday's home clash against Plymouth but recently-appointed boss Chris Wilder has taken the decision to end them prematurely.
Blair returns to parent club Fleetwood having made three starts, scoring once, during his month-long stay at the League two club, while McGinty is now back at Sheffield United on the back of two starts for the Cobblers during the same period.
"I would like to thank both players for their efforts," Wilder said.
"Matty has a minor ankle injury which would have kept him out for this weekend anyway and, with the players coming in, the opportunities for both players here would have been limited moving forwards. I wish both every success in the future.
"In addition, James Hurst is now training back at Crawley. He still has a couple of weeks left on his loan so we can call him back if needed but again his opportunities would be limited so it is best he trains with his parent club."
- Sports & Recreation
- Chris Wilder
- Sheffield United